This invention relates to the television art. Specifically, an interface between a digital microprocessor and a standard NTSC television receiver or monitor is provided for converting binary signals representing a picture to be displayed into a standard NTSC composite video signal.
Since the invention of video games various apparatus have been produced to supply signals to a television receiver for displaying objects on the television receiver. The objects interact and are controlled by individual participants to play a game. Recent video game apparatus has taken advantage of microprocessor systems which enable more complex games to be produced. Data specifying the configuration and location of game objects on a television receiver is manipulated in a microprocessor system. The microprocessor system has a clock rate and a timing system which is related to the scan rate of an NTSC raster scan television receiver. The microprocessor system supplies digital signals indicating the occurrence of synchronization pulses, blanking intervals and a burst signal for establishing a color reference and also provides digital data indicating the color and brightness of each scanned raster on a television receiver. These microprocessor systems are described in a paper given at the 1976 WESCON Professional Program by Kam Li, Kenneth D. Liston, John F. Sluzarski and E. D. Hill as well as in other references.
The microprocessor system requires a digital/video interface for generating a composite video signal from digital words specifying picture detail. The present invention provides such an interface. The output signal from the interface is applied directly to a video monitor for displaying game characters and objects, or the output signal may be used to modulate an RF carrier having a frequency corresponding to the frequency of a broadcast television channel. The modulated signal may then be applied to the antenna terminals of a standard television receiver for viewing game objects.